Prediction of Antenna Induced Biases for Precision GNSS Receivers

Y.C. Chuang, M. Buchanan, A. O’Brien, I.J. Gupta

Abstract:	For precision positioning, navigation and timing applications, GPS receiver measurements must be corrected for antenna induced biases. When a fixed reception pattern antenna is used with a GPS receiver, the antenna induced biases can be pre-calibrated. The same is not true for GPS adaptive antennas or controlled reception pattern antennas (CRPA), where the antenna induced biases can vary with the RF signal environment. A few years ago, we proposed a method for on-the-fly estimation of antenna induced biases for GPS receivers equipped with an adaptive antenna. In this paper, the estimated antenna induced carrier phase biases are verified experimentally. We digitized the live L1 C/A code satellite signals received by a seven-element GPS antenna. These signals are processed in a software defined GPS receiver to obtain the differential carrier phase in the signal received by various antenna elements. The differential phase shows excellent agreement with the expected carrier phase bias for individual antenna elements. We also combined the signals received by various antenna elements using the weights needed to form beams along various satellites. The combined signal was again processed in the software defined receiver to obtain the differential carrier phase for various satellites in view. Again, the measured differential phase is in excellent agreement with the expected antenna induced carrier phase. Finally, we superimposed the digitized GPS data with simulated interfering signals. The superimposed data was processed adaptively to suppress the interfering signals. The adaptively processed data was used with the software defined GPS receiver to obtain the differential carrier phase. This carrier phase also shows excellent agreement with the estimated antenna induce carrier phase biases.
Published in:	Proceedings of the 2014 International Technical Meeting of The Institute of Navigation January 27 - 29, 2014 Catamaran Resort Hotel San Diego, California
Pages:	898 - 903
Cite this article:	Chuang, Y.C., Buchanan, M., O’Brien, A., Gupta, I.J., "Prediction of Antenna Induced Biases for Precision GNSS Receivers," Proceedings of the 2014 International Technical Meeting of The Institute of Navigation, San Diego, California, January 2014, pp. 898-903.
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